JP3207621B2 - Obstacle detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting apparatus for detecting the position of an obstacle using a radar.

2. Description of the Related Art In a vehicle, for example, an automobile, the position of an obstacle in front is known for automatic driving or for alerting a driver to the front. In order to detect the position, especially the direction, of the obstacle, it has been proposed to use a scanning type radar.
Da is very expensive.

For this reason, as shown in JP-A-62-81588, a plurality of light receiving means (receiving means) of a radar are provided so that their light receiving ranges (receiving ranges) partially overlap.
There has been proposed a configuration in which a larger number of detection areas can be set than the plurality of light receiving units. More specifically, for example, two left and right light receiving units are provided, and a left detection region only by the left light reception unit, a right detection region only by the right light reception unit, and a common region detected by both the left and right detection units. There has been proposed an apparatus which can set three areas such that the obstacle can be roughly classified into any of the three areas.

[0004]

However, in the above-mentioned publication, in the overlapping light receiving range where the light receiving ranges partially overlap, the detection accuracy of the detected obstacle is deteriorated, and the detection obstacle is noise or noise. Is difficult to determine. That is, when focusing on a certain light receiving unit,
The detection accuracy is highest at the center position of the light receiving range,
As the position approaches the end of the light receiving range, the detection accuracy becomes worse. Since the above-mentioned overlapping light receiving range is set as a region located near the end of the light receiving range of each light receiving means, obstacle detection accuracy in this overlapping light receiving range becomes poor. Would.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for detecting an obstacle in an overlapping light receiving range with higher accuracy on the assumption that a plurality of receiving means are set so that the receiving ranges partially overlap each other. An object of the present invention is to provide an obstacle detection device.

[0006]

Means for Solving the Problems To achieve the above object, the present invention has the following configuration. That is, as described in claim 1 of the claims, the transmitting means for transmitting the detection signal and the detection signal transmitted from the transmitting means are detected, and the receiving ranges are set so as to partially overlap each other. A plurality of receiving means, and when the levels of the received signals received by the plurality of receiving means are respectively equal to or more than predetermined values, an adding means for adding the received signals of the respective receiving means, And distance determining means for determining a distance to the obstacle based on a later received signal.

[0007] Preferred embodiments of the present invention are as described in claim 2 and the following claims.

[0008]

According to the first aspect of the present invention, the fact that the levels of the received signals at the plurality of receiving means are each equal to or higher than the predetermined value means that the obstacle can be located in the overlapping light receiving range. However, by adding each received signal at this time, the noise level after the addition is randomly generated and is not averaged so much, whereas the noise level after the addition is caused by reflection from an obstacle. The resulting sum of the received signals indicates a large peak value. Therefore, it is possible to accurately determine the distance to an obstacle in the overlapping light receiving range based on the large peak value. By adopting the configuration as described in claim 2, it is preferable to ensure that the reception levels of the two reception units are each equal to or higher than a predetermined level, and to reliably determine the distance to the obstacle. It will be. With the configuration as described in claim 3, the direction to the obstacle can be accurately determined.

With the configuration as described in claim 4, the operation of the adding means is limited to within a predetermined time, and the time for determining a distance using a plurality of received signals is effectively secured. be able to.

[0010] With the configuration as described in claim 5, when the distance to the obstacle is short and the detection accuracy of the obstacle is sufficiently high even in the overlapping light receiving range, the adding means is unnecessarily activated. This is preferable in monitoring the position of an obstacle, especially in the direction of the obstacle.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. Description of FIGS. 1 to 4 In FIG. 1, R is a light emitting / receiving unit provided at a front part and a left and right middle part of an automobile, and the light emitting / receiving unit R has an axis O extending substantially vertically. It has a turntable 1 rotatable about the center. On the turntable 1, one laser light emitting means 2 and two light receiving means PD1, P
D2 is fixed. Laser light is emitted from the light emitting means 2 at predetermined intervals, and the emitted laser light passes through the lens 5, collides with the obstacle B in front, and is reflected.
The reflected laser is received by the light receiving means PD1 or PD2 through the honeycomb filter 6 or 7.

The light receiving range of the light receiving means PD1 is denoted by A1, the light receiving range of the light receiving means PD2 is denoted by A2, and the range in which both the light receiving means PD1 and PD2 can receive light, that is, the overlapping area is denoted by A3. As described above, the area A1 is a detection area mainly including the right front part of the vehicle, the area A2 is a detection area mainly including the left front part of the car, and the area A3 is a detection area.
Is a detection area mainly in front of the center of the vehicle. FIG.
Then, the obstacle B is located substantially at the center of the area A2 and at a relatively short distance. At this time, the light receiving levels of the light receiving means PD1 and PD2 are, as shown in FIG. And the light receiving level in the light receiving means PD1 is smaller than the predetermined level α (it may be zero).

The turntable 1 includes an obstacle B in the area A3.
, That is, the left and right light receiving means PD1 and PD
2 are driven so that the respective light receiving levels are equal to or higher than a predetermined level α, and the state after the driving is shown in FIG.
Thus, the light receiving levels of the left and right light receiving means PD1 and PD2 when the obstacle B is in the area A3 are shown in FIG. When the obstacle B is extremely far, the obstacle B
Is located at the predetermined level α even when the
However, at this time, the obstacle B is regarded as an obstacle that is not a problem.

Driving means for driving the turntable 1 includes:
Although not shown in FIGS. 1 and 3, the servo motor is provided with a servo motor and a potentiometer using a servo mechanism, and the rotary position of the servo motor, that is, the turntable 1 is provided. Is measured by a potentiometer, and the measured rotational position is determined as the direction in which the obstacle B exists.

FIG . 5 (Outline) FIG. 5 shows a drive control system of the light emitting / receiving unit R, and position data of the obstacle B (distance data and direction data in the embodiment ) .
And a control system for obtaining the data. In FIG. 5, the received signals of the light receiving means PD1 and PD2 are detected as current values. The current value detected by PD1 is converted into a voltage by a voltage conversion circuit S1, and then converted by an amplifier S2. The amplified and amplified signal is output to the flip-flop S3 (as a reset signal), and is also output to the control circuit S24 that also serves as direction detection. Similarly, the current value detected by PD2 is converted into a voltage by a voltage conversion circuit
The amplified signal amplified by the signal 12 is output to the flip-flop S13 (as a reset signal) and to the control circuit S24. And the light emitting means 2
Are output (as set signals) to S3 and S13, respectively.

The signals from the flip-flops S3 and S13 are input to a time measuring circuit S21, and the distance measuring circuit receiving the output from S21 finally calculates the distance to the obstacle.

Each of the circuits S1 to S3 is dedicated to PD1,
11 to S13 are set separately and independently for PD2 only. In a specific state described later, PD2
Switch S for adding the output of PD1 to the output of PD1
25 are provided. That is, the switch S25 is
It has a common contact K3 connected to PD1, a switching contact K1 connected between S1 and PD1, and a switching contact K2 connected to S11. Normally, the switching contact K2 is selected, and the received signals of the receiving means PD1 and PD2 are individually processed to determine the position and direction of the obstacle. When the reception level of each of the reception signals PD1 and PD2 is equal to or more than the predetermined value α, the switching contact K1 is selected. At this time, the distance and direction of the obstacle are determined in a state where the received signals (current values) of the respective receiving means are added.

Details of FIG. 5 and Description of FIGS. 6 to 10 Next, an outline of the control in FIG. 5 will be described with reference to FIGS.
Will be described with reference to FIG. FIG. 6 shows the switching contact K1
Alternatively, the manner in which K2 is selected is shown in the form of a time chart, and FIGS. 7 to 9 show the manner of reception levels.

(1) Distance to the obstacle B First, the distance to the obstacle B is determined by the light emission start time (when a set signal of S3 or S13 is inputted) from the light emitting means 2 and the receiving means PD12. Alternatively, the time difference from the time when light is received by PD2 (when a reset signal is input to S3 or S13) is measured in S21,
The distance is calculated in S22 based on the measurement time.
At this time, as shown in FIG. 7, the receiving means PD1 and PD2
When only one of the reception levels is equal to or greater than the predetermined value β (β> α), the distance is determined based on the reception signal indicating the higher reception level (the switching contact is K2
Is selected).

When both reception levels are equal to or higher than the predetermined level α (see FIGS. 8 and 9), the switching contact K1
Is selected, the respective reception levels are added, and on the premise that the added reception level is equal to or larger than the predetermined value β (see FIG. 10), the distance is determined in the same manner as described above. However, when each reception level or addition level is not equal to or more than the predetermined value β, it is determined that the distance to the obstacle B is sufficiently large (an obstacle is a distant obstacle that does not particularly matter,
When there is no need to measure the distance). FIG.
As is clear from FIG. 10 to FIG. 10, since noise is generated at random, when they are added, they show only a noise level substantially equal to the noise level before being added due to their mutual interference.

(2) Measurement of direction When determining the direction, first, the receiving means PD1 and PD2
The driving means S23 is driven so that each of the reception levels of the above (1) and above becomes a predetermined value α or more (the turntable 1 is rotationally driven). Then, the circuit S24 determines the direction of the obstacle B based on the drive position when each of the reception levels is equal to or higher than the predetermined level α (preferably, the position is a position indicating the same reception level). You.
In determining this direction, when each reception level is equal to or higher than the predetermined level α, the switching contact K1 is selected in a state where the driving means S23 is stopped, and the added reception level is equal to or higher than the predetermined value β. It may be performed on the premise that this is the case.

When each of the reception levels is smaller than the predetermined level α, the drive means is set to the neutral position, and when the drive means is set to the neutral position, the area (A1 or A2) The direction is determined as the direction of the obstacle. Note that when both the reception levels do not indicate the predetermined level β or more, the obstacle B is located at a position that is far or largely shifted left and right,
Since the traveling direction is significantly different from the traveling direction of the automobile, it does not pose a problem as an obstacle, so that it is determined that the direction determination is unnecessary.

(3) Others After a lapse of a predetermined time from the selection of the switching contact K1,
It is forcibly switched to the switching contact K2 side. When the measured distance is smaller than the predetermined distance, that is, when the reception level at the receiving means PD1 or PD2 is sufficiently high so that it can be clearly distinguished from noise even when the obstacle B exists in the overlapping area A3. The selection (addition processing) of the switching contact K1 is prohibited.

Description of FIG . 11 Of the control contents described above, the control contents focusing on the switching control of the changeover switch S25 and the rotation drive control of the turntable 1 are shown in the flowchart of FIG. Is shown in Hereinafter, this flowchart will be described. In the following description, P indicates a step. First, at P1, it is determined whether or not the switching contact K1 is currently selected. This P1
If the determination is NO, the count value of the timer is reset to 0 at P2.

After P2, at P3, the light receiving means PD1
It is determined whether or not the light receiving level is equal to or higher than a predetermined value α. If the determination in P3 is YES, in P4, it is determined whether the light receiving level of the light receiving means PD2 is equal to or higher than a predetermined value α. When the determination in P4 is YES, there is a high possibility that the obstacle B is in the area A3. At this time,
At P5, the switching contact K1 is selected, and the received signal is added.

If the determination in P4 is NO, in P6, the turntable 1 is driven to rotate toward the light receiving means PD1, that is, clockwise in FIG. 1, and is driven by the light receiving means PD2 in the direction of detecting an obstacle. Is done. In addition, N is determined by P3.
In the case of O, in P7, it is determined whether or not the light receiving level of the light receiving means PD2 is equal to or more than a predetermined value α. This P7
If the determination is YES, at P8, the turntable 1 is driven to rotate toward the light receiving means PD2, that is, counterclockwise in FIG. 1, and is driven by the light receiving means PD1 in a direction to detect an obstacle. If the determination in P7 is NO, in P9, the turntable 1 is driven to be at the center neutral position.

If the determination in P1 is YES, the timer is counted up in P10, and in P11, it is determined whether or not the count value is equal to or more than a predetermined value.
If the determination in P11 is YES, in P12,
The switching contact K2 is selected. Also, NO in the determination of P11
In P13, it is determined in P13 whether the distance to the obstacle is larger than a predetermined value. When the determination in P13 is NO, the process also proceeds to P12, and the switching contact K2 is selected. If the determination in P13 is YES, the switching contact K1 is kept selected.

Although the embodiment has been described above, three or more light receiving means may be provided. In addition, the direction of the obstacle may be determined by roughly classifying the number of areas, such as the areas A1, A2, and A3, which are set to be larger than the number of light receiving means. Is the driving means S2
3 may not be separately provided. Further, as the detection signal, an ultrasonic wave or the like can be used instead of a laser (light).

[Brief description of the drawings]

FIG. 1 is a diagram showing a light emitting / receiving unit and a detection area.

FIG. 2 is a diagram showing an example of a light receiving level in each light receiving unit in the case shown in FIG.

FIG. 3 is a diagram when the light-emitting / light-receiving unit is rotated from the state of FIG. 1 so that an obstacle is located in a central overlapping light-receiving range.

FIG. 4 is a diagram showing an example of a light receiving level in each light receiving unit in the case shown in FIG.

FIG. 5 is a diagram showing an example of a control system according to the present invention.

FIG. 6 is a time chart showing switching control contents of a changeover switch.

FIG. 7 is a diagram showing a reception level that each receiving unit can take when an obstacle is in an area other than the overlapping area.

FIG. 8 is a diagram showing a reception level that one reception signal can take when an obstacle is in an overlapping area.

FIG. 9 is a diagram showing a reception level that can be taken by another reception signal when an obstacle is in an overlapping area.

FIG. 10 is a diagram showing a reception level that can be obtained when both reception signals are added when an obstacle is in an overlapping area;

FIG. 11 is a flowchart showing switching control of a changeover switch and drive control of a light-emitting / light-receiving unit.

[Description of Signs] R: Light Emitting / Light Receiving Unit 1: Turntable 2: Light Emitting Unit PD1: Light Receiving Unit PD2: Light Receiving Unit S9: Changeover Switch (Addition Unit) S22: Distance Calculation Circuit S24: Also Used for Direction Detection Switching / drive control circuit A3: Overlap area B: Obstacle

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-134041 (JP, A) JP-A-2-143187 (JP, A) JP-A-2-156185 (JP, A) JP-A-5-154185 150045 (JP, A) JP-A-4-148883 (JP, A) JP-A-6-109846 (JP, A) JP-A-7-77577 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ^7/ 48-7/51 G01S 17/00-17/95

Claims (5)

(57) [Claims] 1. A transmitting means for transmitting a detection signal; a plurality of receiving means for detecting a detection signal transmitted from the transmitting means and having a receiving area set to partially overlap each other; When the level of the received signal received by the receiving means is equal to or more than a predetermined value, adding means for adding the received signals of the receiving means, and an obstacle to the obstacle based on the received signal added by the adding means . a distance determining means for determining a distance, obstacle detection device, characterized in that it comprises. 2. The method according to claim 1, Driving means for changing the direction of the plurality of receiving means is provided.
And Reception levels of two of the plurality of receiving means
Are set to be equal to or higher than predetermined levels, respectively.
Drive control means for controlling is provided, The reception levels at the two receiving means are respectively the predetermined levels.
When the level is equal to or higher than the level, the addition by the adding means is performed.
And the distance based on the added reception signal.
The distance to the obstacle is determined by the separation determining means, An obstacle detection device, characterized in that: 3. The method according to claim 1, Driving means for changing the direction of the plurality of receiving means is provided.
And Reception levels of two of the plurality of receiving means
Are set to be equal to or higher than predetermined levels, respectively.
Drive control means for controlling is provided, The reception levels at the two receiving means are respectively the predetermined levels.
The drive position of the drive means when it is at or above the level
Direction determining means for determining the direction of the obstacle based on the
Have been An obstacle detection device, characterized in that: 4. The method of claim 1 or any one of the <br/> Oite of claim 3, wherein the distance determining means, when said adding means is not operating, one of said each receiving means based on the signal received by one receiving means is configured to determine a distance to the obstacle, the operation of the adding means further comprises a limiting means for limiting to be within a predetermined time, and characterized in that Obstacle detection device . 5. The adding means according to claim 1 , wherein the distance to the obstacle determined by the distance determining means is smaller than a predetermined distance. Obstacle further comprising prohibition means for prohibiting the operation of
Object detection device .